Propeller blade sock



July 4, 1961 M. v. WELCH 9.

PROPELLER BLADE SOCK Filed 001;. 19, 1959 INVENTOR. Meme 1/ We/c/v United States Patent 2,990,889 r PROPELLER BIJADE SUCK Merrell V. Welch, Welch Manufacturing, Inc,

Herington, Kans- Filed Oct. 19, 1959, Ser. No. 847,118 8 Claims. (Cl. 170-170) This invention relates to speed control devices for coat propellers and refers more particularly to a device adapted to mount a flexible fin extending outwardly from the operating surface of a propeller for a boat whereby to reduce the speed of the boat at various propeller speeds.

Previously, devices of various sorts have been provided for the purpose of varying the effect of a boat propeller on the water in propelling the boat. These devices have particularly been employed with larger, more powerful motors (outboards) which either cannot run slowly enough to permit trolling or which would suffer injury from prolonged low speed running. However, a number of objections to such available devices, applicable in greater or lesser degree to any given one of such devices, exist. Thus, it is desirable to permit running of an outboard .motor at a speed or rate of revolution which ordinarily would move the boat through the water at, say, five miles per hour, but, with the device applied, actually moves the boat only at a speed of two miles per hour. particularly desirable in the case of trolling in fishing. However, since optional higher speed operation, if the fisherman wishes to move over to another location, say five miles distance, is desired, any sort of propeller attachment preferably should permit such optional high speed operation without removal. For a serviceable speed control, the device should be simple, cheap, readily applied and removed relative to the propeller, not requiring complex adjustment and not detracting excessively from the propeller efficiency at the greater speed. It is also desirable that the attachment protect the propeller blade for shallow water operation.

Therefore, an object of the present invention is to provide a device which may be readily applied to one or Patented July 4, 1961 2 V having three blades, only two of which are fully visible, and having the inventive device applied thereto.

FIG. 2 is a side view of one of the inventive devices removed from the propeller blade.

FIG. 3 is a view taken along the line 33 of FIG. 2 in the direction of the arrows.

FIG. 4 is a fragmentary rear end view of the propeller unit of FIG. 1 with the inventive devices applied.

Referring to the drawings, at 10 is shown a conventional propeller blade housing connected by strut 11 to a motor (not shown) also of conventional type and having extending therebelow a blade protective flange 12. The propeller is mounted rearwardly of strut 11 and flange 12 and propels the housing from left to right in the view of FIG. 1. Propeller hub 13 is rotatably mounted on housing 10 and is driven in forward and reverse rotation by suitable transmission and power connection means of conventional type, not shown. Blades 14, three in number in the particular construction shown, although only two blades are fully visible, are also of conventional form. The direction of rotation of the propeller is seen This is more blades of a propeller which is adaptable to control the effect of the propeller at any rate of speed.

Another object of the invention is to provide a device which is readily applicable to and removable from one or more blades of a propeller, which is relatively cheap to manufacture, has a long life under constant heavy usage, and which is readily accessible for replacement.

Another object of the invention is to provide a device for fitting over one or more of the blades of a boat propeller which operates to control the speed of the boat to some extent a greater degree at a lesser speed and a lesser degree at a greater speed, which device requires absolutely no control or regulation on the part of the boat operator.

Another object of the invention is to provide a device for fitting over one or more of the blades of a propeller for controlling the effectiveness of the propeller at different speeds, no change whatsoever in the propeller or power unit construction being required and no damage resulting either to the propeller or to the boat power unit from use thereof.

Yet another object is to provide such a device which also operates to protect the propeller in shallow water to some extent.

Other and further objects of the invention will appear in the course of the following description thereof.

In the drawings, which form a part of the instant invention and are to be read in conjunction therewith, an embodiment of the invention is shown and, in the various views, like numerals are employed to indicate like arts. p FIG. 1 is a side perspective view of a boat propeller in FIG. 4. All the above structure is conventional and for-ms no part of the instant invention except in so far as it provides the environment for the operation of the invention and the necessary apparatus base therefor.

The invention comprises a blade fitting soc or glove 15 which is formed of resilient, deformable material such as rubber, synthetic rubber, a suitable resilient deformable plastic-rubber composition, or the like. The material of which glove or sock 15 is formed may be of any particular desired thickness, such as of an inch, or the like, provided sufficient strength for the purpose to be described is present. Sock 15' is shaped to fit a particular or conventional type of propeller blade and is deformable to fit thereover and be normally in resilient compression thereon. As the base of conventional propeller blades is of conventionally lesser width than the outer portion thereof, the opening or mouth 16 thereof must be sufficiently expandable to fit over the enlarged outer portion of the blade, whereby to grip the base thereof. A reinforcing strip 17 of like material to that making up the sock may be molded or otherwise attached to the sock or glove surrounding its mouth to reinforce same and provide a more positive grip around the base of the propeller. The tension of the sock to the blade adjacent its base may be slightly greater than the tension around the other portions of the blade, but is not necessarily much greater. Strip 17 may extend outwardly on the leading and following edges of the sock (in forward propeller motion) to reinforce against water pressure. A fin or flange 18 is fixed to or integrally formed with the face of sock 15 which is to overlie that face of the propeller blade which pushes against the water to move the propeller blade housing and boat in forward motion. Pin 18 is preferably rectangular in form (as shown) and preferably extends at least substantially across the said face of the sock or glove 15. The thickness and rigidity of fin 18 is preferably such that, up to some relatively low speed of revolution of the propeller, the fin 18 stands substantially erect and provides a maximum interference with the flow of water over the blade. Past the said limit, the pressure of water moving against the leading face of the fin causes it to bend over, away from the direction of motion of the propeller blade, to a degree commensurate with the increase in velocity of rotation of the propeller. Past a certain speed, the flange then lies flat or substantially fiat on the said face of the sock. To have any substantial effect on the flow of water past the impelling face of the propeller, it is necessary that the fin 18 be positioned at a substantial angle to the direction of rotation of the propeller and preferably substantially normal to a tangent to the path of rotation of the propeller or to the path of rotation itself. The drawing figures show the flange extending across the entire width of the sock face positioned substantially normal to the path of rotation of the blade. The height offthe fin above the base of the sock must be sufiicient to cause the speed reduction to the degree desired. I have discovered that, as a specific example, not intended to be limiting, ina propeller blade having a greatest width of approximately five inches and a working height at right angles to the propeller hub of slightly under 3 /2 inches, that a rubber flange 2% inches long, A of an inch in height and .15 of an inch thick will operate to reduce the effectiveness of a propeller (in terms of thrust) at any propeller r.p.m. approximately /3, with the flange centrally positioned of the sock face as seen in the drawings. A slightly lesser elfect is experienced at higher r.p.m. than at lower r.p.m. due to layover of the flange.

Optional hole 19 operates to bleed off any water entering the sock and must be positioned on the sock trailing edge. While it is possible andfeasible to employ the socks on less than all of the blades of a propeller, particularly on opposed blades in even numbered bladed propellers, in order to avoid asymmetric forces and strain on the motor and propeller, uniform application of the socks to all blades of a propeller is preferred.

In operation, the socks are simply slipped over the propeller blades with the flanges on the operating face of the propeller in rotation of the propeller which drives the boat forwardly. If the flanges are positioned nearer the leading edges of the propeller blades the flanges will probably be of lesser total width than in the example shown in the drawings. When the desired purpose has been served, the socks may be removed from the blades for later replacement. I have found that there is no tendency for my inventive form of propeller socks to come off the propeller at either low or high speeds, evidently due to the pressure of the water counteracting the centrifugal force.

From the foregoing it will be seen that this invention is one well adapted to attain all of the ends and objects hereinabove set forth together with other advantages which are obvious and which are inherent to the structure.

It will be understood that certain features and subcombinations are of utility and may be employed without reference to other features and subcombinations. This is contemplated by and is within the scope of the claims.

As many possible embodiments may be made of the invention without departing from the scope thereof, it is to be understood that all matter herein set forth or shown in the accompanying drawings is to be interpreted as illustrative and not in a limiting sense.

Having thus described mydnvention, I claim:

1. A device for controlling the efiectiveness of a boat propeller comprising a resilient. sleeve sized to fit over a propeller blade and closely fit therearound, said sleeve having an opening therein to receive the blade, and a fin of resilient material fixed to the face of the sleeve positioned over the propeller blade face which acts against the water in forward motion of the propeller, said fin extending across a substantial portion of said sleeve face and positioned at a substantial angle to a line tangent to the path of rotation of the blade,

2. A device as in claim 1 wherein the fin is of a resilience graded to remain erect at a low propeller speed and lie over at a substantially higher propellerspeed.

3. A device as in claim 1 wherein said fin extends substantially perpendicular to the path of rotation of the blade.

4. A device as in claim 1 wherein the fin extends substantially across the sleeve face,

5. A device as in claim 1 wherein the sleeve is reinforced around the opening therein operable to receive the propeller blade.

6. A device as in claim 1 wherein said propeller blade opening in said sleeve is of lesser size than the portion of the blade it engages when positioned operatively on said blade whereby to be in resilient tension thereon.

7. A device as in claim 1 including a bleed hole adjacent the trailing edge thereof.

8. A device for controlling the effectiveness of a boat propeller comprising a plurality of resilient sleeves sized to fit over the blades of a propeller and closely fit therearound, each said sleeve having an opening therein to receive a propeller blade, and a fin of resilient material fixed to the face of each sleeve positioned over the propeller blade face which acts against the water in forward motion of the propeller, each said fin extending across a substantial portion of said sleeve face and positioned at a substantial angle to a line tangent to the path of rotation of the blade.

References Cited in the file of this patent UNITED STATES PATENTS 645,856 Kokernot Mar. 20, 1900 1,055,947 Schwartzberg Mar. 11, 1913 1,066,988 Boutwell July 8, 1913 1,080,964 Gays Dec. 9, 1913 1,757,761 Wendt May 6, 1930 2,222,118 Newnham Nov. 19, 1940 2,374,342 Gaubatz Apr. 24, 1945 2,511,156 Glass June 13, 1950 2,949,092 Fortune Aug. 16, 1960 

